LTE, or Long Term Evolution, also referred to as 3G, refers to research and development involving the third generation partnership project (“3GPP”), which is the name generally used to describe an ongoing effort across the industry aimed at identifying technologies and capabilities that can improve systems such as the universal mobile telecommunications system (“UMTS”). The goals of this broadly based project include improving communication efficiency, lowering costs, improving services, making use of new spectrum opportunities, and achieving better integration with other open standards. The 3GPP LTE project is not itself a standard-generating effort, but will result in new recommendations for standards for the UMTS.
The evolved universal terrestrial radio access network (“E-UTRAN”) in 3GPP includes base stations, providing user plane (including packet data convergence protocol/radio link control/medium access control/physical (“PDCP/RLC/MAC/PHY”) sublayers) and control plane (including radio resource control (“RRC”) sublayer) protocol terminations towards wireless communication devices such as cellular telephones, mobile stations, etc. A wireless communication device is also generally known as user equipment (“UE”). A base station is an entity of a communication network often referred to as a Node B or an NB. Particularly in the E-UTRAN, an “evolved” base station is referred to as an eNB. For details about the overall architecture of the E-UTRAN, see 3GPP Technical Specification (“TS”) 36.300 v1.0.0 (March 2007), which is incorporated herein by reference.
As wireless communication systems such as cellular telephone, satellite, and microwave communication systems become widely deployed and continue to attract a growing number of users, there is a pressing need to accommodate a large and variable number of communication devices transmitting a growing volume of data with fixed resources. Traditional communication system designs employing a fixed communication resource (e.g., a fixed data rate for each communication device) have become challenged to provide high, but flexible, data transmission rates in view of the rapidly growing customer base and expanding levels of service.
A conventional communication mode in a cellular communication system utilizes a base station to establish and control communications between wireless communication devices such as mobile stations carried by subscribers. Accordingly, a base station acts as an intermediary relay link between the wireless communication devices. In this conventional communication mode, each wireless communication device communicates with another wireless communication device employing communication paths between each communication device and the base station (i.e., each wireless communication device indirectly communicates with the other wireless communication device). A more efficient communication mode enables a direct communication path or link between wireless communication devices. Such a direct communication path or link, referred to as a device-to-device (“D2D”) communication path or link, requires granting of communication resources to the directly communicating wireless communication devices.
A grant of communication resources for D2D communications, however, can significantly increase signaling overhead if done in a centralized manner by a base station such as an eNB. One way to reduce the overhead is to allocate communication resources in a fixed manner for all communication devices requesting a D2D connection. A persistent communication resource allocation is spectrally inefficient, as the need for communication resources by communication devices may vary over time such as for discontinuous transmission during a quiet period of a voice call, for a bursty type of packet transmission during gaming, or for instant messaging, etc. Moreover, a fixed communication resource allocation is not adaptive to accommodate network load variations or variations in communication path characteristics. For example, when new services are established or when services are completed from time to time, the system may need to reconfigure frequency or time slot resources, or may need to reallocate existing services to improve spectral utilization. Hence, there is a need to allocate communication resources for D2D communication in a dynamic fashion, but at the same time provide flexibility of communication resource allocation with a reduced impact on base station signaling overhead. These issues are particularly important in time division duplex (“TDD”) communication systems because various transmit/receive traffic slot configurations can significantly increase signaling overhead.
There have been attempts in the past to address peer-to-peer (“P2P”) communications between user equipment in a communication system. For instance, International Patent Application Publication No. WO 2006/067683, entitled “Method and Apparatus for Eliminating P2P Interference in P2P-Enabled Communication Systems,” by D. Shang, et al., published Jun. 29, 2006, which is incorporated herein by reference, describes a method for an initial resource allocation for P2P communication between user equipment, but no description is provided for efficient utilization of these communication resources.
Therefore, what is needed in the art is a system and method that provides efficient and dynamic management of communication resources in a wireless communication system that avoids the deficiencies of conventional systems.